Im7

Im7 is a Colicin Immunity Protein that binds to the nuclease domain of Colicin E7, in order to protect the cell producing the Colicin from the DNase Activity. When it binds to colicin E7 it physically blocks off the major dsDNA binding sites.

This structure shows the Immunity protein bound to the ColE7 cytotoxic domain.

3D structures of colicin-E7 immunitiy protein
Colicin Immunity Protein